Tape pulling mechanism



pril 2 0, 1937. E. W GENT 2,077,925

TAPE PULLING MECHANISM l Filed May 11, 1935 s sheets-sheet 2 /Nl/ENTOR E W `GE NT BVJW -I A A TTORNEV April 20, 1937. E. w. GENT y 2,077,925

` TAPE PULLING MEGHANISM Filed May 11,*1935 5 Sheets-Sheet 3 /NVENTOR .By EWGENT WLM Patented Apr. 20, 1937.`

UNITED 'STATES PATENT ori-ICE Bell Telephone laboratories,

Incorporated,-

New York, N. Y., a corporation of New York Application May 1l, 1935, Serial No. 20,980

8 Claims.

This invention relates. to tape pulling mechanisms and more particularly to mechanisms for pulling the record strip of tape delivered by a telegraph printer for display by an optical projecting system.

It is -an object of the invention toprovide a tape pulling mechanism for cooperation with a telegraph printer lin which clutches and friction drives are avoided and the tape is pulled by a l positive connection between the pulling drum and the drivingmotor.

Another object is to provide a mechanism of vthis type which is electrically driven and is controlled principally-by the tension in the tape.

A further object is to provide a tape pulling mechanism that will not require changes in the telegraph printer which thus may remain of standard design.

A tape pulling mechanism in accordance with this invention is capable of being used with a page printer but is particularly adapted for use with a tape printer, such as the well-known news tickers.

News tickers are frequently operated in combination with an optical projecting system through which the printed tape is` fed so that the record will be exposed to light and an image transmitted by a lensv system and mirrors to a diS- play screen. In such an arrangement it is essential that the tape emanating from"` the printer be taut while passing through the ileld'of exposure in the projector.

In accordance with the invention the tape pulling mechanism receives the tape from the projector on a pulling drum; an electric motor, which may be a stepping magnet with a ratchet wheel, drives the drum positively through the medium of a spring member such as a helical or spiral spring. `The circuit for the stepping 4g magnet may be controlled by contacts in the ticker, these contacts closing the circuit during each printing operation so that the tape will be pulled taut each time the feeding mechanism in the printerv delivers a piece of tape; the pull on the tape is not suicient to overcome the retaining force asserted on the tape by the feeding mechanism inthe printer.

'I'he motor or magnet circuit is, furthermore, controlled by a pair of contacts which-open when a predetermined maximum tension is set up by the puller in the tape. The take-up mechanism should be adjusted to have a tendency to take up more tape than is fed out by the printer; thus while the printer is feeding tape the tape puller will have a tendency to pull a greater amount (Cl. P18-42) of tape, but being unable to do so the pulling drum will fall behind the driving motor and a tension will be set up in the intervening motor spring which consequently becomes distorted. This distortion is taken advantage of in accordance with the invention to open the last mentioned pair of contacts so that the motor or stepping device may be stopped until the pulling drum again catches up with the motor.`

Such an arrangement is particularly desirable when the pulling drum is used as a storing reel, in which cas'e the effective diameter of the pulling drum, of course, varies with the amount of tape stored thereon. 0n account of this the pulling drum will tend to pull thetape at a much greaterrate when the reel is full than when it is empty; since the stepping Amagnet operates at constant speed and must operate fast enough to keep the tape taut when the reel is empty, it is essential that the magnet circuit be interrupted when the reel is partly or completely filled every time the tension in the tape increases beyond a desired maximum. l

The contact control in response'to tape tension may be accomplished in various ways, the main principle being that the control contacts be heldin engagement by means of a spring acting with a tension on the contacts which is in proportion to the maximum allowable tension in the tape, and that this spring be included in the driving circuit between the motor and the drum so that it will be subject to increased tension and will open the contacts when the tension in the tape becomes too high. The contact operating spring may be distorted longitudinally or angularly and it may bel a separate spring or may form an intermediate or an end portion of the main power spring; it may be a helical or a spiral spring or it may be a flat spring distorted by bending or by twisting, or combinations ofV these.

The device may, of course, be operated in conjunction with mechanism for preventing jerky movement of the tape.

These and other features, capabilities and advantages of the invention will appear from the following description of certain specic embodiments of the invention which are illustrated in the accompanying drawings, in which:

Fig. 1 is a diagrammatical view of a projecting system and tape pulling means constructed according to the invention;

Fig. 2 is a side View of the upper portion of Fig. 1;

Fig. 3 is an enlarged view showing more in detail a printing mechanism andan optical system with which the tape pulling mechanism may be operated;

Fig. 4 is a horizontal elevation of the printing mechanism shown in Fig. 3;

Figs. 5, 6 and 7 are perspective dagrammatical views of tape pulling mechanisms, comprising the main features of the invention.

It is to be understood that various changes and modifications may be made in the details of 'construction shown in the drawings without departing from the spirit of the invention as set forth in the appended claims.

In general, the projecting system comprises a compartment 20 containing a recording device 30, such as a tape printer or news ticker, together with a tape pulling mechanism and an optical system |00 for observing the recorded message and projecting it upward into a second compartment |0`which is placed directly above the lower compartment at a xed distance therefrom, so that the recorded message can be reproduced on a vertical screen where it may be viewed from the front by an assembly of people. Y

The recording device 30 may be any standard tape printer or news ticker, with a supply roll of standard printing tape. For a disclosure of a device suitable forthe-purpcses of the invention, reference should be had to United States Patent 1,989,710, issued to A. H. Reiber at al. on February 5, 1935. Only such details of the recording device Will be illustrated and described herein as are necessary for an understanding of the invention and its operation.

Referring to the drawings, the printer 30, the projecting mechanism and the tape pulling mechanism 60 are contained in a general structure, preferably of wood, having a lower compartment 20 and an upper compartment |0. The lower compartment 20 contains the tape pulling means -60, the prismatic mirrors |03 and |04, the tape illuminating means |0|, the objective or lens system |01, etc. The upper compartment I0 is open at the bottom and contains the inclined mirrors and I2 and the translucent screen I3. Compartment I0 issupported above compartment 20 by means of the posts |4 or in any other suitable manner whereby the two compartments are combined into a structurall unit which may be supported on a table or on the floor.

The printer 30 illustrated in the drawings 'is of a type particularly suited for the optical system in that it permits the projecting system to observe and project the printed message as nearly as possible to the last character printed.

The printer 30 carries a supply roll 32`I of standard transparent paper strip 3| which is led over a tape guiding bar 33 between the tape feed wheel 34 and the feed pressure wheel 35,

and thence underneath the color ribbon 5| and over the platen 38 at the point of printing 55. The platen 38 is journaled in bearings 39. The tape 3| is positively fed along by the feed wheel 34 every `time -the main bail plunger 42 is operated in response to a signal. Immediately upon reception bythe printer magnet of each signal combination the main bail plunger 42 is "operated and causes main bail 45 to operate lever arm 46 thereby causing pawl 36, which is controlled by spring 31, to engage and rotate the tape feedv wheel 34. Operation of main bail"45 causes pawl 40, which iscontrolled by spring 4I, to engage and rotate the platen 38, Operation of Amain bail 45 also causes' one of the type bars 50 or a special stunt to be operated, depending upon the signal. Operation of main bail plunger 42 operates lever arm 43 which is suitably attached to main bail plunger 42 and which closes the contacts of springs 44 once for each operation thereby establishing a circuit to the tape pulling mechanism 60.v

The tape 3| is then passed between prismatic mirrors |03 and |04 and between the tape guide rollers |.05 and |06 to the tape reel 6| which is attached to shaft 62 of the tap pulling mechanism 60. This mechanism 60, in a manner yet to be explained, functions to keep the tape 3| taut between the feed wheel 34 and the tape guide rollers |05 and |06 in order to insure accurate focus and proper illumination of all parts of the typewritten message lying between the prismatic mirrors |03 and |04.

The optical system comprises an illuminating means |0| of any suitable kind, a prismatic mirror |03 to deflect the light through the tape 3| and a prismatic mirror ,|04 to deflect the image on the part of the tape 3| which i`s between the prismatic mirrors |03 and |04, upward through the objective or lens system |01 and through the top covering of compartment 20. The image is received inthe upper compartment by mirror which is placed at an angle with the axis of the lens system |01 so that the image is inverted and thrown greatly enlarged onto mirror I2 which again inverts the image and throws it onto the translucent screen I3. The light from lamp |0| is intensiiied by lens'l02 which may be designed in well-known manner to blur the image of the lamp filament on the tape 3| so that the record will appear evenly illuminated on the screen 3.

The color ribbon 5| during the operation of the printer 30, is fed from ribbon spool 52 through one arm of the color ribbon guide 54 across the tape 3| at the'point of printing 55 thence through the other arm of the color ribbon guide 54 to the second ribbon spool 53. v'

One embodiment of the tape pulling mechanism is particularly illustrated in Fig. 5; the device is shown in a diagrammatic manner to bring out its main features and principles of operation, the details of construction being unimportant for an understanding of the invention. The device comprises a shaft 62 which carries a mounting 51 for'a tape reel 6| adapted for easy detachment from the mounting aswell as for simple detachment of the printer tape 3| in any desirable manner well known in the art. At the other end of the shaft 62 is a ratchet wheel 64 free to rotate about the shaft and connected to the shaft through a long helical spring 13, one end of which is attached to the ratchet wheel and the other end to a. block 18 fastened to the shaft. The ratchet wheel is driven thrugh a stepping pawl 65 attached at 61 to an armature 66 pivoted at 1l, the armature in turn being operated by electromagnet 63 and the return spring 12. 'I'he pawl 65 is kept in engagement with the ratchet by means of spring 10 and the travel of the pawl may be limited in any desirable manner as by front and back stops 68 and 69 for the armature 66. A spring pressed ratchet prevents the ratchet wheel 64 from rotating backwards.

A pair of control contacts 16 and 11 are arranged for preventing the tape puller from exerting an excessive pull on the tape 3|. 'I'he circuit from these contacts extends overXconduc-v tor 19, slip ring 83 insulated by bushing"82 from shaft 62, brush 85, conductor 81, contacts 44 on the printer, conductor 89, winding of -electromagnet 63, conductor 90, battery 9|, conductor 88, brush 86, uninsulated slip ring 84, shaft 62, block 18 and contact 11. The contact 16 is carried by a iioating arm 14 and is insulated therefrom by insulation 15. The arm 14 is attached to spring 13 in any desirable manner as by passing a portion of the spring 13 into a slot 80 in the arm 14.

For an understanding of the operation of this device it must be pointed out that the movement of the tape 3| is controlled by the feed roller 34 in the printer, which pushes the tape out of the printer through proper guides; by means of the spring-pressed roller 35 the tape is not only positively moved by the feed roller 34 but it is also held with considerable force by the feed roller 33 against movement by an lexternal force. However, the arrangement is such that the shape of the hook on stepping pawl 36 and the tension of spring 31 for the stepping pawl obviates all danger of the tape breaking when the tape is pulled out of the printer by hand. The movement of the platen 33 simultaneously with the feed movement serves to aid in the feeding of the tape past the point of printing.

Referring now to the tape puller, it will be assumed that the tape 3i has been attached to the reel 6| which in turn has .been placed on the mounting 51. For proper operation of the device it will usually be necessary to tighten the tape 3| between the printer and the puller. I'his may be done in different ways as byadvancing the ratchet wheel .64 by hand or by manually closing and opening the stepping circuit for magnet 63 until sucient tension is set up in the spring 13 to hold the tape 2| taut. As the tension in spring 13 increases its various turns will be shifted with respect to each other, andwhen a certain tension has been set up in the spring I with the result that the contacts 16 and 11 are separated. The arrangement is such that the portion of spring 13 which is placed between block '18 and arm 14 will always have a certain tension which corresponds to the maximum pull to which the tape 3| may be subjected; it is, therefore, apparent that it is when this tension is slightly increased by the stepping device that the contacts 13 and 11 will be opened to immediately interrupt the stepping operations. The spring 11 is designed to be of suicient strength to hold the right hand portion of spring 13 under tension by engagement with the contact 18 even when the left end of spring l13 attached tol ratchet wheel 34 is completely released. I

Thus assuming that the device has been set up and ready for operation the contacts 16 and 11 may either be closed or opened; it will be assumed that these contacts are left closed. When a printing operation takes place in the printer 30, the rod 42 will be operated to oscillate once in the vertical direction, thereby closing contacts 44 and operating magnet 63 once. The consequent stepping of the ratchet wheel 64 increases the tension in the left portion of 'spring 13; at the same time the tape 3| is fed out from the printer and causes a degree of release in the reel is nearly filled with tape.

y tape pulling device.

tend to increase the tension in spring 13 and the feeding of tape 3| will tend to decrease the tension in the spring. -When the reel is newly started the decrease in tension of the spring is much greater for each printer operation than when the It is, therefore, necessary that the stepping magnet increase the tension in spring 13 during each step sufiiciently `to slightly more than oifset,the maximum relaxation caused by each step of feeding of tape 3| when the reel is nearly empty. This may, of course, be accomplished in various ways as by providing the proper number of teeth on ratchet wheel 34, or by causingv the pawl 65 to travel over a plurality of teeth in each operation, or by providing proper gearing between the ratchet 64 and the attachment for spring 13. Thus, under all conditions the ratchet wheel will gradually increase the tension in the left hand end of spring 13 until it is slightly greater than the normal tension in the right hand end of spring 13, at which time the contacts 16 and 11 will be opened and prevent further stepping of the magnet 33 until further feeding of the tape 3| again relaxes the tension in the left hand end of spring 13 suiiiciently to again bring contacts 16 and 11 into engagement; the stepping magnet will then again be permitted to follow the printer operations and to gradually wind the spring 13 until the contacts 16 and 11 again become opened.v

It will thus be seen that the tension in the tape 3| can never exceed a tension which is predetermined by means of the tension set up in the right hand end of spring 13 between block 18 and armature 13. t is also apparent that the tape puller will not be active during stunt operations of the printer when no tape is being fed.

Itis evident that the portion of spring 13 which lies between the blocks .18 and 16 may be a spring separate from the left hand end of spring 13,

and that in that case it may be attached between any of the parts attached to the shaft 62 by means of block 18 and the parts carried by arm 14 and that it may be of any shape so long as it tendsA to force the contacts 16 and 11 against each other. In the general projectingsystem described above the insertion of the prisms 103 and |04 into theprinter would probably require a slight modification of certain parts mounted on the shelf 56. it should, however, be understood that this modification of the standard printer is for the sake of adapting the printer for the optical system and is not required `for the proper opera.- tion of the tape pulling device i6. Contacts such as contacts 44 are usually present in standard printers. In the majority of cases it will therefore not be necessary to subject the printing device to any change at all for operation with the It is, furthermore, possible to eliminate the control of the tape puller b y the printer contacts 44, as illustrated in the embodiments shown in Figs. 6 and 7. v

Referring particularly to Fig. 6, atape pulling device is shown in diagrammaticalform which may be arranged for pulling atape Without storing the tape or may be provided with a storing reel. 'Ihe device is very similar` to the one shown in Fig. 5 but differs incertain respects as will appear from the following description.

The power spring 13 is connected between ratchet wheel 64 and shaft 62 for positive driving ofthe disc 58 which may be adapted either for a pulling drum or for reception of a storing reel. The disc 58 carries a contact ring l2| which has an insulated insert |22 and is insuiated from the disc 58. A brush |23 serves to connectthe battery 9| to the ring l2 Thearm 14 is mounted as by a sleeve I|| to rotate freely on the shaft 62.

It carries a contact member 16 adapted to engage the contact ring |2|. A brush |24 serves to continue the battery circuit from brush |23, ring |2| over contact member 16 and hub The arm 14 is clamped .at its outer end to a point on the spring 13 for rotation of the sleeve in ac-l cordance with the distortion of the spring 13.

In this case the operating circuit for the stepping magnet 63 is made self-interrupting by means of the contact 92 which will open up every time the armature 66 is attracted.

'In this arrangement there is not set up a constant tension in the right hand portion of the spring 13 as in the arrangement shown in Fig. 5.

When the device is idle and the tape has just been placed about the pulling drum the position of the different parts may be as shown in the drawings with spring 13 fully relaxed and the insert.` |22 a predetermined angle removed from the arm 16. Upon closing of switch 93 the stepping circuit for the magnet will be completed as follows: From batteryv 9|,.over switch 93, feed contact |23, ring |2|, contact arm 16, hub feed brush |24, armature 66, contact 92 and winding of magnet 63 to the other side of battery 9|. The magnet will commence a series of stepping operations whereby the spring 13 becomes wound and the arm 14 with its associated contact member 16 will be rotated. The drum will remain stationary, being held back by the feeding roller in the printer.

When the arm 16 reaches thel insulated segment |22 the stepping circuit is opened and the operation stops. In this mannerthe tape will be under a predetermined tension which, of course, should be insufficient to pull it out of the printer.

When now the printer commences to print and feed tape the pulling drum and disc 58 will begin to rotate, again bringing the ring |2| into contact with the now stationary contact member 16. The stepping circuit is again closed and will remain closed until the arm 16 catches up with the insulated segment |22 at which time the tape 3| will be under the maximum permissible tension and the stepping operation ceases. functions will continuously alternate as longas the printer operates. f

It is, of course, possible to` govern the speed of the stepping operations in a desirable manner so that when the device is used as a tape puller without a storing reel the stepping operation may be practically continuous with very few interruptions by the segment |22. The governing device may be a governor on the shaft 62 or any wellknown damping means attached to the armature 66.

The device shown on Fig. 7 has a self-interrupting circuit shown in Fig. 6, but may if desired have a circuit such as that shown in Fig. controlled by contacts 44 in the printer. The power f from the ratchet wheel 64 is supplied through one spring section |13 which may be a flat spiral spring attached to the shaft 62; the other portion ofthe driving spring is in the form of a flat spring |14 mounted directly on the disc 58 which in this case is loosely mounted on the shaft 62.

The tension from spring |13 is supplied through shaft 62 to the arm 14 which thereby is brought into engagement with the spring |14. The contact spring 16 is in this case mounted on an insulating support on the disc 58 and is connected These two i through insulated slip ring 83 to the stepping circuit.

When the device has been prepared for operation the contacts 16 and |14 will ordinarily be in engagement. Upon closing of the switch 93 the stepping circuit is completed as follows: From battery,9|, over switch 93, brush |23, spring |14, contact 16, slip ring 83, self-interrupting contact 92, magnet 63 and back to battery. The device Will begin stepping thereby increasing the tension in spring |13, rotating shaft 62 and bringing the arm 14 into engagement with the spring |14. When the tension in spring |13 becomes great enough to overcome the tension with which spring |14 rests against contact 16 the stepping circuit will be opened. When now the printer begins to print and feed the tape 3| the flexing of spring |14 due to the pressure of arm 14 will force the disc 58 to rotateunder the released tension from the tape 3|. As soon as the contact is again made between contact/16 and spring |14 the stepping circuit will be closed and the arm 14 will again begin to Aflex the spring |14 for continued operation of the disc 58 until the spring disengages the contact 16.

What is claimed is:

1. A `strip pulling mechanism for a strip fed from a telegraph printer or the like comprising a pulling drum for the strip, a motor electrically controlled overa circuit, a driving spring system between said motor and said drum, contact means included in said circuit, and contact operating means for closing and opening said circuit by said contact means when the tension in said spring system decreases and increases, respectively, said spring system including a spring for maintaining a tension in said tape under all operating conditions. n

2. A strip pulling mechanism for the printing strip fed out from a telegraph printer comprising a pulling drum for the strip, a motor electrically controlled over a circuit, contact means included in said circuit for starting and stopping said motor, contact operating means for closing said contact means with a pressure, a driving spring for transmitting power from said motor to said drum,Y said contact operating means being mounted to rotate with said spring and to open said contacts when the transmitted torque increasessuliciently to overcome said pressure.

3. A strip pulling mechanism for pulling without appreciable slack a strip fed from a strip feeding mechanism, such as a telegraph printer, at a varying rate determined by said feed mechanism comprising a rotating drum for exerting a pull on said 'strip, v an electric motor having an operating circuit, spring means for transmitting driving power from said motor to said drum, contact means affixed for revolution with a point on said spring means, contact making means aiiixed for revolution with another point on said spring means for opening and closing said circuit at said vcontact means as the tension in said spring means contact operating member mounted to rotate.. about said axle and connected for positive rota-ff tion with the other end of saidspring section,.a

`connected between said motor and said reel forv rotation of said reel with said'motor and that l said pair of contacts are mounted to be separated by the distortion of portion only of said iiexible member due to increased tension in 'the tape.

6. A tape pulling mechanism for continuously pulling a tape taut against a back tension applied to the tape by a tape feed mechanism such as included in a telegraph printer for intermittent feeding of the the tape which comprises a. pulling drum adapted to pull the tape under tension, a

motor connected for driving of said drum, a rst contact member, a second contact member, a circuit controlled by said contact members for starting and stopping said motor, a coil spring connected to said motor to drive said drum, said iirst contact member being attached for rotation with one end of said spring, and said second contact member being attached for rotation with an intermediate point on said spring to keep said circuit closed under tension from said spring when the pull on said tape -is normal and to open said circuit under tension from said spring when the pull on said tape is greater than normal.

7. In combination, a telegraph tape printer having means for feeding the tape and for opposing pulling of the tape by external means and having contacts which Vare temporarily closed once by each printing operation, and a tape pulling mechanism for constantly pulling the tape taut during'normal operations, said mechanism comprising a pulling drum for the tape, a-driv 'l ing member and a driven member in engagement *for rotating said reel when a slack in the tape 5 occurs, a power spring section -for rotating said driving member with one end, a stepping magnet with ratchet wheel for winding the other end of said spring section, a current supply circuit for said magnet controlled by saiiil contacts for step- 10 ping of said ratchet wheel for each printer operation, other contacts for controlling said supply circuit and operable by said members to open `when said members disengage due to tension in the tape, and another power spring section for l5 holding said members in engagement with a pressure. v

8. In combination, a. telegraph printer having -means for feeding the tape and for opposing pulling of the tape by external means and having 20 contacts closed and opened once for each printer operation and a tape pulling mechanism for constantly pulling the tape taut during normal operations, said pulling mechanism comprising a' winding-up reel for the tape, a power spring 25 having one end attached to said reel for driving thereof instantly the tape is fed by said printer, a stepping magnet'with ratchet `wheel for winding of said spring, circuit connections between said contacts and said magnetfor stepping of 30 I said ratchet wheel once for each tape feed opera- .tion when the reel is nearly empty; other cony tacts included in said connections and attached 4for operation by said power spring in'accordance with the tension in a section only thereof to out '35 out steppings of said ratchet as the reel becomes lled with tape, said power spring exerting a continuous pull on said reel irrespective of the positions of any of said contacts.

L Y EDGAR w.ciEN 'r.l 

